With Manufacturer's Scan Tool
Function 03: Output Diagnostic Test Mode (DTM)
Performing Output Diagnostic Test Mode
Special tools and equipment
- Scan Tool (ST) VAG 1551 or VAG 1552 with cable VAG 1551/3
Test conditions
- Main fuses OK.
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical consumers, e.g. lights and rear window heating must be switched off.
Prerequisites (with air conditioning)
- Vehicle at room temperature, warmer than + 15 degree C (59 degree F)
- A/C on
- Lowest temperature setting and highest blower speed
The Output diagnostic test mode activates the following components in the following sequence:
1. Cold Start Injector -N108-
2. EGR Vacuum Regulator Solenoid Valve -N18-
3. Air Conditioning compressor interrupt
4. Fuel Cut-off Valve -N109-
5. Wastegate Bypass Regulator Valve -N75- for boost control
6. Glow Plug Relay -J52-
7. Glow Plug Indicator Lamp -K29-
8. Relay -J359- preheat coolant, low heat output (man. trans. only)
9. Relay -J360- preheat coolant, high heat output (man. trans. only)
10. Malfunction Indicator Lamp (MIL) -K82-, Exhaust Warning Lamp -K83- (MIL is shown in the 1551 display, however; -K83- Exhaust Warning Lamp is the actual component being tested)
NOTE:
- Activation of individual control elements is limited to 30 seconds. but can be stopped at any time by pressing button.
- Ignition must be switched off before repeating Output Diagnostic Test Mode.
Work sequence
- Connect Scan Tool (ST) VAG 1551/(VAG 1552). With engine idling select Engine Control Module (ECM) with "Address word" 01 (Connecting Scan Tool (ST) and selecting ECM. [1][2][3]Connecting VAG 1551 Scan Tool)
Indicated on display:
Rapid data transfer HELP
Select function XX
- Operate Scan Tool (ST) and advance through program sequence by following display.
- Press buttons -0- and -3- for "Output Diagnostic Test Mode" (DTM).
Indicated on display:
Rapid data transfer HELP
03 Output Diagnostic Test Mode (DTM)
Activating Cold Start Injector -N108-:
- Press -Q- button to enter input.
Indicated on display:
Final control diagnosis ->
Cold Start Injector -N108
Activating the valve, influences the noise of combustion considerably (pre-ignition).
If no changes in the combustion noises are heard:
- Check injection adjuster control range. Diesel Injection Timing Control Range, Checking
Activating EGR Vacuum Regulator Solenoid valve -N18-:
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode
Exhaust Gas Regulator Valve -N18
Valve must click.
NOTE: It is difficult to hear the valve click due to engine noise. Determine valve operation by feel (touch).
Valve does not click:
- Check EGR Vacuum Regulator Solenoid Valve -N18-
Activating air conditioning compressor interrupt:
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
A/C Compressor interrupt
Air conditioner compressor switch-off is checked.
The test step is also called on vehicles without air conditioner system.
A/C compressor must stop within 5 seconds (visual check) then start approx. every 5 seconds and then stop.
If A/C compressor does not switch off:
- Check signals from/to air conditioning system. Testing and Inspection
Activating Fuel Cut-off Valve -N109-:
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode Fuel cut-off valve -N109
The engine must stop.
If engine does not stop:
- Switch off ignition.
- Unscrew fuel shut-off valve and remove any metal particles or dirt, item 4 .
- Repeat Output Diagnostic Test Mode, if engine will not stop replace Fuel Cut-off Valve -N109-.
- Continue Output Diagnostic Test Mode with engine stopped and ignition switched on.
Activating Wastegate Bypass Regulator valve -N75-:
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
Wastegate Bypass Regulator Valve -N75-
The solenoid valve must click.
NOTE: The clicking operation of the valve is difficult to hear and is therefore best checked by touch.
If the solenoid valve does not operate:
- Check charge pressure control solenoid valve -N75-:
Activate Glow Plug Relay -J52-:
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
Glow plug relay -J52
Vehicles through MY > 2001
Relay must click.
Switching relay on and off can also be observed by the brightening and
dimming of the interior light as a result of glow plug power consumption.
If relay does not click:
- Check glow plug relay:
Vehicles from MY 2002>
NOTE: This engine has a Glow Period Control Module - J370- installed. It is not possible to optically and acoustically check the activation, this is only possible by connecting a current pick-up clamp to the glow plug wiring. Testing and Inspection
Continued for all vehicles
Activate glow period warning lamp (K29):
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
Glow Plug Indicator Lamp -K29
Glow Plug Indicator Light -K29- does not blink:
Glow Plug Indicator Light -K29- must blink.
- Check Glow Plug Indicator Lamp -K29-:
Activating Relay for low heat output -J359- (only on vehicles with manual transmission):
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
Low heater output relay -J359
The relay must click.
If the relay does not click:
- Check low heat output relay:
Activating Relay for high heat output -J360- (vehicles with manual transmission):
- Press -> button.
Indicated on display:
Output Diagnostic Test Mode ->
High heater output relay -J360
The relay must click.
If the relay does not click:
- Check relay for preheating coolant, high heat output -J360-.
Activating Malfunction Indicator Lamp (MIL) and Switch -K82-:
- Press -> button.
Output Diagnostic Test Mode
Malfunction Indicator Lamp (MIL) Indicated on display:
MIL must flash.
MIL does not flash:
- Check Malfunction Indicator Lamp (MIL) and Switch -K82-:
- Press -> button.
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -6- for "End output" and confirm with -Q- button.
- Switch off ignition.